content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
   * Other names may be trademarks of their respective owners.]
   *
   * -------------------
   * CrosshairState.java
   * -------------------
   * (C) Copyright 2002-2008, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 24-Jan-2002 : Version 1 (DG);
   * 05-Mar-2002 : Added Javadoc comments (DG);
   * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
   * 19-Sep-2003 : Modified crosshair distance calculation (DG);
   * 04-Dec-2003 : Crosshair anchor point now stored outside chart since it is
   *               dependent on the display target (DG);
   * 25-Feb-2004 : Replaced CrosshairInfo --> CrosshairState (DG);
   * ------------- JFREECHART 1.0.x ---------------------------------------------
   * 13-Oct-2006 : Fixed initialisation of CrosshairState - see bug report
   *               1565168 (DG);
   * 06-Feb-2007 : Added new fields and methods to fix bug 1086307 (DG);
   * 26-Jun-2008 : Now tracks dataset index (DG);
   *
   */
  
  package org.jfree.chart.plot;
  
  import java.awt.geom.Point2D;
  
  /**
   * Maintains state information about crosshairs on a plot between successive
   * calls to the renderer's draw method.  This class is used internally by
   * JFreeChart - it is not intended for external use.
   */
  public class CrosshairState {
  
      /**
       * A flag that controls whether the distance is calculated in data space
       * or Java2D space.
       */
      private boolean calculateDistanceInDataSpace = false;
  
      /** The x-value (in data space) for the anchor point. */
      private double anchorX;
  
      /** The y-value (in data space) for the anchor point. */
      private double anchorY;
  
      /** The anchor point in Java2D space - if null, don't update crosshair. */
      private Point2D anchor;
  
      /** The x-value for the current crosshair point. */
      private double crosshairX;
  
      /** The y-value for the current crosshair point. */
      private double crosshairY;
  
      /**
       * The dataset index that the crosshair point relates to (this determines
       * the axes that the crosshairs will be plotted against).
       *
       * @since 1.0.11
       */
      private int datasetIndex;
  
      /**
       * The index of the domain axis that the crosshair x-value is measured
       * against.
       *
       * @since 1.0.4
       */
      private int domainAxisIndex;
  
      /**
       * The index of the range axis that the crosshair y-value is measured
       * against.
       *
       * @since 1.0.4
       */
      private int rangeAxisIndex;
  
      /**
       * The smallest distance (so far) between the anchor point and a data
       * point.
       */
      private double distance;
  
      /**
       * Creates a new <code>CrosshairState</code> instance that calculates
       * distance in Java2D space.
       */
      public CrosshairState() {
          this(false);
      }
  
      /**
       * Creates a new <code>CrosshairState</code> instance.
       *
       * @param calculateDistanceInDataSpace  a flag that controls whether the
       *                                      distance is calculated in data
       *                                      space or Java2D space.
       */
      public CrosshairState(boolean calculateDistanceInDataSpace) {
          this.calculateDistanceInDataSpace = calculateDistanceInDataSpace;
      }
  
      /**
       * Returns the distance between the anchor point and the current crosshair
       * point.
       *
       * @return The distance.
       *
       * @see #setCrosshairDistance(double)
       * @since 1.0.3
       */
      public double getCrosshairDistance() {
          return this.distance;
      }
  
      /**
       * Sets the distance between the anchor point and the current crosshair
       * point.  As each data point is processed, its distance to the anchor
       * point is compared with this value and, if it is closer, the data point
       * becomes the new crosshair point.
       *
       * @param distance  the distance.
       *
       * @see #getCrosshairDistance()
       */
      public void setCrosshairDistance(double distance) {
          this.distance = distance;
      }
  
      /**
       * Evaluates a data point and if it is the closest to the anchor point it
       * becomes the new crosshair point.
       * <P>
       * To understand this method, you need to know the context in which it will
       * be called.  An instance of this class is passed to an
       * {@link org.jfree.chart.renderer.xy.XYItemRenderer} as
       * each data point is plotted.  As the point is plotted, it is passed to
       * this method to see if it should be the new crosshair point.
       *
       * @param x  x coordinate (measured against the domain axis).
       * @param y  y coordinate (measured against the range axis).
       * @param domainAxisIndex  the index of the domain axis for this point.
       * @param rangeAxisIndex  the index of the range axis for this point.
       * @param transX  x translated into Java2D space.
       * @param transY  y translated into Java2D space.
       * @param orientation  the plot orientation.
       *
       * @since 1.0.4
       */
      public void updateCrosshairPoint(double x, double y, int domainAxisIndex,
              int rangeAxisIndex, double transX, double transY,
              PlotOrientation orientation) {
  
          if (this.anchor != null) {
              double d = 0.0;
              if (this.calculateDistanceInDataSpace) {
                  d = (x - this.anchorX) * (x - this.anchorX)
                    + (y - this.anchorY) * (y - this.anchorY);
              }
              else {
                  double xx = this.anchor.getX();
                  double yy = this.anchor.getY();
                  if (orientation == PlotOrientation.HORIZONTAL) {
                      double temp = yy;
                      yy = xx;
                      xx = temp;
                  }
                  d = (transX - xx) * (transX - xx)
                      + (transY - yy) * (transY - yy);
              }
  
              if (d < this.distance) {
                  this.crosshairX = x;
                  this.crosshairY = y;
                  this.domainAxisIndex = domainAxisIndex;
                  this.rangeAxisIndex = rangeAxisIndex;
                  this.distance = d;
              }
          }
  
      }
  
      /**
       * Evaluates an x-value and if it is the closest to the anchor x-value it
       * becomes the new crosshair value.
       * <P>
       * Used in cases where only the x-axis is numerical.
       *
       * @param candidateX  x position of the candidate for the new crosshair
       *                    point.
       * @param domainAxisIndex  the index of the domain axis for this x-value.
       *
       * @since 1.0.4
       */
      public void updateCrosshairX(double candidateX, int domainAxisIndex) {
  
          double d = Math.abs(candidateX - this.anchorX);
          if (d < this.distance) {
              this.crosshairX = candidateX;
              this.domainAxisIndex = domainAxisIndex;
              this.distance = d;
          }
  
      }
  
      /**
       * Evaluates a y-value and if it is the closest to the anchor y-value it
       * becomes the new crosshair value.
       * <P>
       * Used in cases where only the y-axis is numerical.
       *
       * @param candidateY  y position of the candidate for the new crosshair
       *                    point.
       * @param rangeAxisIndex  the index of the range axis for this y-value.
       *
       * @since 1.0.4
       */
      public void updateCrosshairY(double candidateY, int rangeAxisIndex) {
          double d = Math.abs(candidateY - this.anchorY);
          if (d < this.distance) {
              this.crosshairY = candidateY;
              this.rangeAxisIndex = rangeAxisIndex;
              this.distance = d;
          }
  
      }
  
      /**
       * Returns the anchor point.
       *
       * @return The anchor point.
       *
       * @see #setAnchor(Point2D)
       *
       * @since 1.0.3
       */
      public Point2D getAnchor() {
          return this.anchor;
      }
  
      /**
       * Sets the anchor point.  This is usually the mouse click point in a chart
       * panel, and the crosshair point will often be the data item that is
       * closest to the anchor point.
       * <br><br>
       * Note that the x and y coordinates (in data space) are not updated by
       * this method - the caller is responsible for ensuring that this happens
       * in sync.
       *
       * @param anchor  the anchor point (<code>null</code> permitted).
       *
       * @see #getAnchor()
       */
      public void setAnchor(Point2D anchor) {
          this.anchor = anchor;
      }
  
      /**
       * Returns the x-coordinate (in data space) for the anchor point.
       *
       * @return The x-coordinate of the anchor point.
       *
       * @since 1.0.3
       */
      public double getAnchorX() {
          return this.anchorX;
      }
  
      /**
       * Sets the x-coordinate (in data space) for the anchor point.  Note that
       * this does NOT update the anchor itself - the caller is responsible for
       * ensuring this is done in sync.
       *
       * @param x  the x-coordinate.
       *
       * @since 1.0.3
       */
      public void setAnchorX(double x) {
          this.anchorX = x;
      }
  
      /**
       * Returns the y-coordinate (in data space) for the anchor point.
       *
       * @return The y-coordinate of teh anchor point.
       *
       * @since 1.0.3
       */
      public double getAnchorY() {
          return this.anchorY;
      }
  
      /**
       * Sets the y-coordinate (in data space) for the anchor point.  Note that
       * this does NOT update the anchor itself - the caller is responsible for
       * ensuring this is done in sync.
       *
       * @param y  the y-coordinate.
       *
       * @since 1.0.3
       */
      public void setAnchorY(double y) {
          this.anchorY = y;
      }
  
      /**
       * Get the x-value for the crosshair point.
       *
       * @return The x position of the crosshair point.
       *
       * @see #setCrosshairX(double)
       */
      public double getCrosshairX() {
          return this.crosshairX;
      }
  
      /**
       * Sets the x coordinate for the crosshair.  This is the coordinate in data
       * space measured against the domain axis.
       *
       * @param x the coordinate.
       *
       * @see #getCrosshairX()
       * @see #setCrosshairY(double)
       * @see #updateCrosshairPoint(double, double, double, double,
       * PlotOrientation)
       */
      public void setCrosshairX(double x) {
          this.crosshairX = x;
      }
  
      /**
       * Get the y-value for the crosshair point.  This is the coordinate in data
       * space measured against the range axis.
       *
       * @return The y position of the crosshair point.
       *
       * @see #setCrosshairY(double)
       */
      public double getCrosshairY() {
          return this.crosshairY;
      }
  
      /**
       * Sets the y coordinate for the crosshair.
       *
       * @param y  the y coordinate.
       *
       * @see #getCrosshairY()
       * @see #setCrosshairX(double)
       * @see #updateCrosshairPoint(double, double, double, double,
       * PlotOrientation)
       */
      public void setCrosshairY(double y) {
          this.crosshairY = y;
      }
  
      /**
       * Returns the dataset index that the crosshair values relate to.  The
       * dataset is mapped to specific axes, and this is how the crosshairs are
       * mapped also.
       *
       * @return The dataset index.
       *
       * @see #setDatasetIndex(int)
       *
       * @since 1.0.11
       */
      public int getDatasetIndex() {
          return this.datasetIndex;
      }
  
      /**
       * Sets the dataset index that the current crosshair values relate to.
       *
       * @param index  the dataset index.
       *
       * @see #getDatasetIndex()
       *
       * @since 1.0.11
       */
      public void setDatasetIndex(int index) {
          this.datasetIndex = index;
      }
  
  }
  